Coniine, chemical structure

The data shown in Table 2 illustrate the general paucity of comparative toxicity data within an isosteric series of chemicals. In this Table a variety of toxic end-points observed for benzene and naphthalene have been compared with those of their simple heterocyclic analogues, and it is clear that it is almost impossible to derive chemical structure-biological activity relationships from the published literature for even such a simple series of compounds. Even basic estimates of mammalian toxicity such as LD50 values cannot be accurately compared due either to the absence of relevant data or the noncomparability of those available. Thus in a field where there are little comparative data on the relative toxicity to mammals of pyrrole, thiophene and furan for example, it is difficult to relate chemical structure to biological activity in historical heterocyclic poisons such as strychnine (3) and hemlock [active agent coniine (4)]. 

Coniine possesses a similar chemical structure to that of pelletierine (Section 4.2), isolated from the stem bark and root bark of Punka granatum. Thus Robinson [3] estimated coniine to be derived biosynthetically from a lysine moiety and a C4 unit as in the case of pelletierine, and as shown in the following figure. However, when [2- " C]lysine or its metabolites, [l,5- C2]cadaverine or [6- " C]-A -piperideine, were fed to hemlock,none of the alkaloids isolated from this plant were labeled. 

Nigrifactin is a product of Streptomyces sp. No. FFD-101, and it possesses antihistaminic effects [l].The chemical structure of this alkaloid was determined mainly through spectral interpretation [2] and confirmed by chemical synthesis [3].Through structure elucidation studies, it was clarified that nigrifactin possessed a similar partial structure to those of coniine and pel-letierine, described previously. 

The most important and toxic of these is coniine, which has a chemical structure similar to nicotine [13, 14, 80]. Coniine is a neurotoxin, which disrupts the workings of the central nervous system and is toxic to humans and all classes of livestock [85]. Ingestion in any quantity can result in respiratory collapse and death. 

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